Merge pull request #24 from gruntwork-io/xdcr-fix

Update xdcr example to work better with Terraform Registry

Author: brikis98

examples/couchbase-multi-datacenter-replication/main.tf

@@ -3,16 +3,6 @@
 # This is an example of how to deploy two Couchbase clusters in AWS with replication between them.
 # ---------------------------------------------------------------------------------------------------------------------
 
-provider "aws" {
-  alias  = "primary"
-  region = "${var.aws_region_primary}"
-}
-
-provider "aws" {
-  alias  = "replica"
-  region = "${var.aws_region_replica}"
-}
-
 terraform {
   required_version = ">= 0.10.3"
 }
@@ -110,7 +100,7 @@ data "template_file" "user_data_primary" {
     cluster_port     = "${module.couchbase_security_group_rules_primary.rest_port}"
 
     replication_dest_cluster_name       = "${var.cluster_name_replica}"
-    replication_dest_cluster_aws_region = "${var.aws_region_replica}"
+    replication_dest_cluster_aws_region = "${data.aws_region.replica.name}"
   }
 }
 
@@ -433,3 +423,7 @@ data "aws_subnet_ids" "default_replica" {
 
   provider = "aws.replica"
 }
+
+data "aws_region" "replica" {
+  provider = "aws.replica"
+}

examples/couchbase-multi-datacenter-replication/providers.tf

@@ -0,0 +1,20 @@
+# ---------------------------------------------------------------------------------------------------------------------
+# CONFIGURE THE PRIMARY AND REPLICA PROVIDERS FOR THIS EXAMPLE
+# Note that we do this in a separate file so the automated tests can override it and set custom regions in these
+# providers. Ideally, we'd use Terraform file overrides instead, but those do not properly override provider aliases
+# in Terraform 0.11. This may be fixed in Terraform 0.12.
+# ---------------------------------------------------------------------------------------------------------------------
+
+provider "aws" {
+  alias = "primary"
+
+  # Region intentionally ommitted so this example will prompt the user for a region when run via Terraform Registry
+  # instructions
+}
+
+provider "aws" {
+  alias = "replica"
+
+  # Region intentionally ommitted so this example will prompt the user for a region when run via Terraform Registry
+  # instructions
+}

examples/couchbase-multi-datacenter-replication/variables.tf

@@ -17,42 +17,32 @@
 # ---------------------------------------------------------------------------------------------------------------------
 
 variable "ami_id_primary" {
-  description = "The ID of the AMI to run in the cluster in var.aws_region_primary. This should be an AMI built from the Packer template under examples/couchbase-ami/couchbase.json. Leave blank to use one of the example AMIs we have published publicly."
+  description = "The ID of the AMI to run in the primary cluster. This should be an AMI built from the Packer template under examples/couchbase-ami/couchbase.json. Leave blank to use one of the example AMIs we have published publicly."
   default     = ""
 }
 
 variable "ami_id_replica" {
-  description = "The ID of the AMI to run in the cluster in var.aws_region_replica. This should be an AMI built from the Packer template under examples/couchbase-ami/couchbase.json. Leave blank to use one of the example AMIs we have published publicly."
+  description = "The ID of the AMI to run in the replica cluster. This should be an AMI built from the Packer template under examples/couchbase-ami/couchbase.json. Leave blank to use one of the example AMIs we have published publicly."
   default     = ""
 }
 
-variable "aws_region_primary" {
-  description = "The AWS region to deploy the primary Couchbase cluster into (e.g. us-east-1)."
-  default     = "us-east-1"
-}
-
 variable "cluster_name_primary" {
   description = "What to name the primary Couchbase cluster and all of its associated resources"
   default     = "couchbase-server-primary"
 }
 
-variable "aws_region_replica" {
-  description = "The AWS region to deploy the replica Couchbase cluster into (e.g. us-east-1)."
-  default     = "us-west-1"
-}
-
 variable "cluster_name_replica" {
   description = "What to name the replica Couchbase cluster and all of its associated resources"
   default     = "couchbase-server-replica"
 }
 
 variable "ssh_key_name_primary" {
-  description = "The name of an EC2 Key Pair that can be used to SSH to the EC2 Instances in the primary Couchbase cluster. Must be a Key Pair in var.aws_region_primary. Set to an empty string to not associate a Key Pair."
+  description = "The name of an EC2 Key Pair that can be used to SSH to the EC2 Instances in the primary Couchbase cluster. Must be a Key Pair in the same region as the primary cluster. Set to an empty string to not associate a Key Pair."
   default     = ""
 }
 
 variable "ssh_key_name_replica" {
-  description = "The name of an EC2 Key Pair that can be used to SSH to the EC2 Instances in the replica Couchbase cluster. Must be a Key Pair in var.aws_region_replica. Set to an empty string to not associate a Key Pair."
+  description = "The name of an EC2 Key Pair that can be used to SSH to the EC2 Instances in the replica Couchbase cluster. Must be a Key Pair in the same region as the replica cluster. Set to an empty string to not associate a Key Pair."
   default     = ""
 }
 

test/couchbase_multi_datacenter_replication_test.go

@@ -9,6 +9,9 @@ import (
 	"github.com/gruntwork-io/terratest/modules/random"
 	"github.com/gruntwork-io/terratest/modules/terraform"
 	"github.com/gruntwork-io/terratest/modules/aws"
+	"github.com/gruntwork-io/terratest/modules/files"
+	"os"
+	"github.com/gruntwork-io/terratest/modules/logger"
 )
 
 const clusterNamePrimaryVarName = "cluster_name_primary"
@@ -23,6 +26,9 @@ const savedUniqueIdPrimary = "UniqueIdPrimary"
 const savedAwsRegionReplica = "AwsRegionReplica"
 const savedUniqueIdReplica = "UniqueIdReplica"
 
+const providersFile = "providers.tf"
+const providersFileBackup = "providers.tf.bak"
+
 func TestIntegrationCouchbaseEnterpriseMultiDataCenterReplicationUbuntu(t *testing.T) {
 	t.Parallel()
 	testCouchbaseMultiDataCenterReplication(t, "ubuntu", "enterprise")
@@ -90,6 +96,8 @@ func testCouchbaseMultiDataCenterReplication(t *testing.T, osName string, editio
 		terraformOptions := test_structure.LoadTerraformOptions(t, couchbaseMultiClusterDir)
 		terraform.Destroy(t, terraformOptions)
 
+		restoreProvider(t, couchbaseMultiClusterDir)
+
 		amiIdPrimary := test_structure.LoadString(t, couchbaseMultiClusterDir, savedAmiIdPrimary)
 		amiIdReplica := test_structure.LoadString(t, couchbaseMultiClusterDir, savedAmiIdReplica)
 
@@ -119,6 +127,8 @@ func testCouchbaseMultiDataCenterReplication(t *testing.T, osName string, editio
 		uniqueIdPrimary := test_structure.LoadString(t, couchbaseMultiClusterDir, savedUniqueIdPrimary)
 		uniqueIdReplica := test_structure.LoadString(t, couchbaseMultiClusterDir, savedUniqueIdReplica)
 
+		overrideProvider(t, couchbaseMultiClusterDir, awsRegionPrimary, awsRegionReplica)
+
 		terraformOptions := &terraform.Options{
 			TerraformDir: couchbaseMultiClusterDir,
 			Vars: map[string]interface{} {
@@ -152,3 +162,54 @@ func testCouchbaseMultiDataCenterReplication(t *testing.T, osName string, editio
 	})
 }
 
+const providerOverrideTemplate = `
+# This file temporarily overrides the providers at test time. The original providers file should be restored at the
+# end of the test!
+
+provider "aws" {
+  alias  = "primary"
+  region = "%s"
+}
+
+provider "aws" {
+  alias  = "replica"
+  region = "%s"
+}
+`
+
+// In order for the examples to work well with the Terraform Registry, where they are wrapped in a module, we cannot
+// define the AWS regions in those providers. This works OK for manual usage, where the user can specify the region
+// interactively, but not at test time. Therefore, as a workaround, we override the providers.tf file at test time
+// with the regions fully defined, and then put it back at the end of the test in the restoreProvider function.
+func overrideProvider(t *testing.T, couchbaseMultiClusterDir string, awsRegionPrimary string, awsRegionReplica string) {
+	providersFilePath := filepath.Join(couchbaseMultiClusterDir, providersFile)
+	providersFileBackupPath := filepath.Join(couchbaseMultiClusterDir, providersFileBackup)
+
+	logger.Logf(t, "Backing up %s to %s", providersFilePath, providersFileBackupPath)
+	if err := files.CopyFile(providersFilePath, providersFileBackupPath); err != nil {
+		t.Fatal(err)
+	}
+
+	newProvidersFileContents := fmt.Sprintf(providerOverrideTemplate, awsRegionPrimary, awsRegionReplica)
+
+	logger.Logf(t, "Creating override proviers file at %s with contents:\n%s", providersFilePath, newProvidersFileContents)
+	if err := files.WriteFileWithSamePermissions(providersFilePath, providersFilePath, []byte(newProvidersFileContents)); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// See the overrideProvider method for details
+func restoreProvider(t *testing.T, couchbaseMultiClusterDir string) {
+	providersFilePath := filepath.Join(couchbaseMultiClusterDir, providersFile)
+	providersFileBackupPath := filepath.Join(couchbaseMultiClusterDir, providersFileBackup)
+
+	logger.Logf(t, "Restoring %s from %s", providersFilePath, providersFileBackupPath)
+	if err := files.CopyFile(providersFileBackupPath, providersFilePath); err != nil {
+		t.Fatal(err)
+	}
+
+	logger.Logf(t, "Deleting %s", providersFileBackupPath)
+	if err := os.Remove(providersFileBackupPath); err != nil {
+		t.Fatal(err)
+	}
+}